import java.util.Scanner;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: Lily
 * Date: 2024-11-08
 * Time: 21:32
 */
public class test_3 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        char[] s = in.next().toCharArray();

        int[] sum = new int[2]; // 统计字符串中所有 0 和 1 的个数
        for (int i = 0; i < n; i++) {
            sum[s[i] - '0']++;
        }

        int left = 0, right = 0, ret = 0, half = n / 2;
        int[] count = new int[2]; // 统计窗⼝内 0 和 1 的个数
        while (right < n - 1) // 细节问题
        {
            count[s[right] - '0']++;
            while (right - left + 1 > half) {
                count[s[left++] - '0']--;
            }
            if (right - left + 1 == half) {
                if (count[0] * 2 == sum[0] && count[1] * 2 == sum[1]) {
                    ret += 2;
                }
            }
            right++;
        }

        System.out.println(ret);
    }
}
